Summary

The influence of social factors on birthweight and fetal and infant mortality was investigated in the Swiss birth cohort from 1979–85 (N=519 933). The proportion of newborns with low-birthweight (<2500 g) was higher in lower social classes. Stillbirth-rate, neonatal and postneonatal mortality were higher in lower social classes, too. When controlling for birthweight, the increase in mortality in the lower social classes became somewhat less striking. Marked social differences in perinatal mortality were found in the newborns with normal weight, whereas almost no difference could be detected in the low-birthweight-group.